In Belgian Pat. No. 892589 there are described oxazaphosphorin-4-thio-alkanesulfonic acids and specific salts thereof of the general formula: ##STR3## In the preceding formula R.sub.1, R.sub.2, and R.sub.3 which can be the same or different, stand for hydrogen, methyl, ethyl, 2-chloroethyl or 2-methanesulfonyloxyethyl, wherein at least two of those residues are 2-chloroethyl and/or 2-methanesulfonyloxyethyl, R.sub.4 is hydrogen or methyl, X is a straight or branched chain C.sub.2 -C.sub.6 alkylene which can have a mercapto group on the 1-, 2-, 3-, 4-, or 5-carbon atoms of the alkylene chain, and Y.sup..sym. is the hydrogen cation, an alkali or alkaline earth cation, the guanidinium, morpholinium or cyclohexylammonium cation or the cation which is derived from an amine of the formula NR.sub.5 R.sub.6 R.sub.7 wherein the residues R.sub.5 to R.sub.7 are the same or different and are hydrogen, C.sub.1 -C.sub.2 -alkyl groups or hydroxyethyl groups, or Y.sup..sym. is the ethylenediammonium cation H.sub.3 N.degree.--CH.sub.2 --N.degree.H.sub.3 or the piperazinonium cation and z is 1 where Y.degree. is a monobasic cation, or z is 2 where Y.sup..sym. is a dibasic cation of the cation of a compound having two monobasic cations.
Furthermore, the German published application No. 3133309 concerns 4-carbamoyloxyoxaphosphorine derivatives of the general formula ##STR4## wherein X is oxygen or sulfur, R.sub.1, R.sub.2, and R.sub.3 can be the same or different and represent hydrogen, methyl, ethyl, 2-chloroethyl or 2-methanesulfonyloxyethyl, the residues R.sub.4 can be the same or different and represent hydrogen, methyl or ethyl, R.sub.5 is hydrogen, C.sub.1-4 -alkyl, hydroxy-C.sub.1-4 -alkyl or phenyl and Z among others also is a C.sub.1 -C.sub.18 -alkylamino group, which can contain different substituents, among others the carboxy group and their pharmaceutically usable salts. In this German OS there is described as example a compound wherein Z is the group --NH--CH.sub.2 --COOH and the corresponding cyclohexylamine salt.
The compounds of Belgian Pat. No. 892589 and German published application No. 3133309 possess antitumor action as well as an immunosuppresive action.